<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #box{
            width: 150px;
            height: 200px;
            background-color: forestgreen;

            position: fixed;
            left: -150px;
        }
        #box span{
            position: absolute;
            width: 30px;
            text-align: center;
            background-color: hotpink;
            color: #fff;
            right: -30px;
            top: 80px;
        }
    </style>
</head>
<body>

    <div id="box">
        <span>分享到</span>
    </div>
    <script src="jquery.js"></script>
    <script>
        /*
        需求：鼠标移入box，显示box
              鼠标移出box，隐藏
        */
       $('#box').hover(function(){
        $(this).animate({left:0})
       },function(){
        $(this).animate({left:-150})
       })
    </script>
</body>
</html>